Go implementation of Fibonacci Numbers

Source: https://i.pinimg.com/originals/1f/e2/8b/1fe28baa0f0bdcf02a506911f156f324.jpg

While learning go language you may have encountered with an exercise to implement Fibonacci numbers with go function closures. Here is how I implemented it.

package main
import "fmt"
// fibonacci returns a function which returns an int.( a closure)
func fibonacci() func() int {
 before, after := 0, 1
 return func() int {
  rtn := before
  before, after = after, before+after
  return rtn
 }
}
func main() {
 f := fibonacci() // a function closure is return
 for i := 0; i < 10; i++ {
  fmt.Println(f())
 }
}

Do note that after always contain the value which gets returned in the next round.